Q: I have planted tulips and zantedeschia (calla & narcissis) in containers, but i live in an apartment on the 9th floor. This is my first effort for balcony planting. How can I protect the bulbs from freezing? My apartment faces south and I get most of the day's sunshine when the sun is out. I had thought of wrapping them in newspaper and put them in a plastic bag to help ward off the cold weather. Would that work?
Definitely try growing spring-blooming bulbs over winter on a balcony if you live in zone 6 and warmer. In colder areas, they’ll freeze in most situations. Another option is to buy potted daffodils in early spring at garden centres, home centres, supermarkets and floral shops. For “instant spring” plant out the potted plants once hard frosts are past.
To grow bulbs on balconies
In winter, try to minimize the chilling effects of winter wind exposure. You mention wrapping the pots and positioning them in the balcony’s most protected area. Try wrapping pots in bubble wrap secured with strong tape or burlap. Plant in the largest possible winter-proof containers, placing bulbs deep and away from pot sides.
After bloom save bulbs for planting again next fall by letting the foliage yellow to provide bulbs time to re-charge their stored energy, then lift them to store indoors until fall. Or, just enjoy your blooms and then discard the fading plants. Calla lilies (Zantedeschia) are summer bloomers at peak July to October.
In late spring, buy callas as potted bedding plants or grow the bulbs yourself. Callas can be started up early indoors, then planted out after threat of frost is past and night temperatures remain over 40°F. To plant bulbs directly into outdoor pots, soil temperature should be above 15°C or 60° F.
At season’s end, callas grown in pots can be brought indoors to continue growing over-winter as houseplants. Callas are tender summer bulbs hardy in zones 7 to 10.